The present embodiments relate to a power amplifier unit for a magnetic resonance device.
Magnetic resonance devices are known, for example, for clinical applications. In this case, nuclear spins of an examination object aligned via a transmission antenna are excited in the magnetic resonance device, and the image data is recorded by a receiver coil. High power levels are used to operate the transmission antenna and are made available by a power amplifier unit. The power amplifier unit may be incorporated into a transmission unit of the magnetic resonance device.
Power amplifier units may include various power modules (e.g., four power modules) that may generate an output power of 5-8 kW, so that in combination, a power of, for example, 30 kW may be obtained. Where symmetrical signals are used in order to generate the high power levels, an asymmetrical signal is used to control the transmission antenna, so that signals generated by the power amplifier modules are asymmetrized using a balun (e.g., a balancing unit).
Power amplifier units, in which each power amplifier module is operated separately, are known. The asymmetrical output signals from the individual power amplifier modules are combined with one another in order to obtain the desired output signal from the power amplifier unit. Signals between the power amplifier units realized as individual devices may be transported with the aid of coaxial cables. The main disadvantage of this is that the high-power amplifier units or the power amplifier modules occupy a large space, which is undesirable. A compact design is not possible with the known power amplifier units.